at86rf401 ATMEL Corporation, at86rf401 Datasheet - Page 20

• Manufacturer Part Number: at86rf401
• Description: Smart Rf Wireless Data Microtransmitter
• Manufacturer: ATMEL Corporation

The X, Y and Z Registers
Figure 9. The X, Y and Z Registers
Arithmetic Logic Unit
(ALU)
In-system Self-
programmable Flash
Program Memory
20
X Register
Y Register
Z Register
AT86RF401
15
70
R29 ($1D)
15
70
R30 ($1F)
15
70
R27 ($1B)
The registers R26...R31 have some added functions to their general-purpose usage.
These registers are address pointers for indirect addressing of the data space. The
three indirect address registers X, Y and Z are defined as shown in Figure 9.
In the different addressing modes, these address registers have functions as fixed dis-
placement, automatic increment and decrement (see the descriptions for the different
instructions).
The high-performance AVR ALU operates in direct connection with all the 32 general-
purpose working registers. Within a single clock cycle, ALU operations between regis-
ters in the register file are executed. The ALU operations are divided into three main
categories: arithmetic, logical and bit-functions. The multiplier is not present in this ver-
sion of the core. Therefore, the MUL instruction is not supported.
The AT86RF401 contains 2 Kbytes of on-chip Flash memory for program storage. Since
all instructions are 16- or 32-bit words, the Flash is organized as 1K x 16.
The Flash memory has an endurance of at least 1000 write/erase cycles. The PC is 10
bits wide, thus addressing the 1024 program memory locations. See the Memory Pro-
gramming section (page 13) for a detailed description on Flash data serial downloading.
Constant tables can be allocated within the entire program memory address space (see
Table 22, Instruction Set, page 45).
ZH
0
XH
0
YH
0
ZL
7
R31 ($1E)
XL
7
R26 ($1A)
YL
7
R28 ($1C)
0
0
0
0
0
0
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